Ninja: Allow compilation before generation of dependencies' private sources

This requires knowing when a generated header is public, which we can
model using file sets.  Add policy CMP0154 to treat generated sources
as private by default in targets with file sets.  Generated public
headers can be specified in public file sets.

Fixes: #24959
Issue: #15555

33 files changed, 320 insertions, 15 deletions

diff --git a/Help/command/add_custom_command.rst b/Help/command/add_custom_command.rst
index 1fcf06c..5fe4326 100644
--- a/Help/command/add_custom_command.rst
+++ b/Help/command/add_custom_command.rst
@@ -87,6 +87,11 @@ The options are:
     :ref:`Target-dependent expressions <Target-Dependent Queries>` are not
     permitted.
 
+  .. versionchanged:: 3.28
+    In targets using :ref:`file sets`, custom command byproducts are now
+    considered private unless they are listed in a non-private file set.
+    See policy :policy:`CMP0154`.
+
 ``COMMAND``
   Specify the command-line(s) to execute at build time.
   If more than one ``COMMAND`` is specified they will be executed in order,
@@ -270,6 +275,11 @@ The options are:
     :ref:`Target-dependent expressions <Target-Dependent Queries>` are not
     permitted.
 
+  .. versionchanged:: 3.28
+    In targets using :ref:`file sets`, custom command outputs are now
+    considered private unless they are listed in a non-private file set.
+    See policy :policy:`CMP0154`.
+
 ``USES_TERMINAL``
   .. versionadded:: 3.2
 
diff --git a/Help/command/add_custom_target.rst b/Help/command/add_custom_target.rst
index ef0c8d9..0385a93 100644
--- a/Help/command/add_custom_target.rst
+++ b/Help/command/add_custom_target.rst
@@ -63,6 +63,11 @@ The options are:
     :ref:`Target-dependent expressions <Target-Dependent Queries>` are not
     permitted.
 
+  .. versionchanged:: 3.28
+    In custom targets using :ref:`file sets`, byproducts are now
+    considered private unless they are listed in a non-private file set.
+    See policy :policy:`CMP0154`.
+
 ``COMMAND``
   Specify the command-line(s) to execute at build time.
   If more than one ``COMMAND`` is specified they will be executed in order,
diff --git a/Help/command/target_sources.rst b/Help/command/target_sources.rst
index 4a8eda2..86bf7fb 100644
--- a/Help/command/target_sources.rst
+++ b/Help/command/target_sources.rst
@@ -60,6 +60,8 @@ expressions to ensure the sources are correctly assigned to the target.
 See the :manual:`cmake-buildsystem(7)` manual for more on defining
 buildsystem properties.
 
+.. _`File Sets`:
+
 File Sets
 ^^^^^^^^^
 
diff --git a/Help/manual/cmake-policies.7.rst b/Help/manual/cmake-policies.7.rst
index a018aff..dff4f34 100644
--- a/Help/manual/cmake-policies.7.rst
+++ b/Help/manual/cmake-policies.7.rst
@@ -57,6 +57,7 @@ Policies Introduced by CMake 3.28
 .. toctree::
    :maxdepth: 1
 
+   CMP0154: Generated files are private by default in targets using file sets. </policy/CMP0154>
    CMP0153: The exec_program command should not be called. </policy/CMP0153>
    CMP0152: file(REAL_PATH) resolves symlinks before collapsing ../ components.  </policy/CMP0152>
 
diff --git a/Help/policy/CMP0154.rst b/Help/policy/CMP0154.rst
new file mode 100644
index 0000000..cb93d41
--- /dev/null
+++ b/Help/policy/CMP0154.rst
@@ -0,0 +1,53 @@
+CMP0154
+-------
+
+.. versionadded:: 3.28
+
+Generated files are private by default in targets using :ref:`file sets`.
+
+CMake 3.27 and below assume that any file generated as an output or byproduct
+of :command:`add_custom_command` or :command:`add_custom_target` may be a
+public header file meant for inclusion by dependents' source files.  This
+requires :ref:`Ninja Generators` to add conservative order-only dependencies
+that prevent a target's source files from compiling before custom commands
+from the target's dependencies are finished, even if those custom commands
+only produce sources private to their own target.
+
+:ref:`File Sets`, introduced by CMake 3.23, provide a way to express the
+visibility of generated header files.  CMake 3.28 and above prefer to
+assume that, in targets using file sets, generated files are private to
+their own target by default.  Generated public headers must be specified
+as members of a ``PUBLIC`` (or ``INTERFACE``) ``FILE_SET``, typically of
+type ``HEADERS``.  With this information, :ref:`Ninja Generators` may omit
+the above-mentioned conservative dependencies and produce more efficient
+build graphs.
+
+This policy provides compatibility for projects using file sets in targets
+with generated header files that have not been updated.  Such projects
+should be updated to express generated public headers in a file set.
+For example:
+
+.. code-block:: cmake
+
+  add_custom_command(
+    OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/foo.h
+    ...
+  )
+  target_sources(foo
+    PUBLIC FILE_SET HEADERS
+      BASE_DIRS ${CMAKE_CURRENT_BINARY_DIR}
+      FILES     ${CMAKE_CURRENT_BINARY_DIR}/foo.h
+  )
+
+The ``OLD`` behavior for this policy is to assume generated files are
+public, even in targets using file sets, and for :ref:`Ninja Generators`
+to produce conservative build graphs.  The ``NEW`` behavior for this
+policy is to assume generated files are private in targets using file sets,
+and for :ref:`Ninja Generators` to produce more efficient build graphs.
+
+This policy was introduced in CMake version 3.28.  Use the
+:command:`cmake_policy` command to set it to ``OLD`` or ``NEW`` explicitly.
+Unlike many policies, CMake version |release| does *not* warn
+when this policy is not set and simply uses ``OLD`` behavior.
+
+.. include:: DEPRECATED.txt
diff --git a/Help/release/dev/fileset-private-dep.rst b/Help/release/dev/fileset-private-dep.rst
new file mode 100644
index 0000000..5ffb036
--- /dev/null
+++ b/Help/release/dev/fileset-private-dep.rst
@@ -0,0 +1,7 @@
+fileset-private-dep
+-------------------
+
+* Generated files, in targets using :ref:`file sets`, are now considered
+  private by default.  Generated public headers must be specified using
+  file sets.  This allows :ref:`Ninja Generators` to produce more
+  efficient build graphs.  See policy :policy:`CMP0154`.
diff --git a/Source/cmGlobalNinjaGenerator.cxx b/Source/cmGlobalNinjaGenerator.cxx
index 30305a1..7368a6a 100644
--- a/Source/cmGlobalNinjaGenerator.cxx
+++ b/Source/cmGlobalNinjaGenerator.cxx
@@ -1278,6 +1278,13 @@ std::string cmGlobalNinjaGenerator::OrderDependsTargetForTarget(
   return cmStrCat("cmake_object_order_depends_target_", target->GetName());
 }
 
+std::string cmGlobalNinjaGenerator::OrderDependsTargetForTargetPrivate(
+  cmGeneratorTarget const* target, const std::string& config) const
+{
+  return cmStrCat(this->OrderDependsTargetForTarget(target, config),
+                  "_private");
+}
+
 void cmGlobalNinjaGenerator::AppendTargetOutputs(
   cmGeneratorTarget const* target, cmNinjaDeps& outputs,
   const std::string& config, cmNinjaTargetDepends depends) const
@@ -3176,3 +3183,10 @@ std::string cmGlobalNinjaMultiGenerator::OrderDependsTargetForTarget(
   return cmStrCat("cmake_object_order_depends_target_", target->GetName(), '_',
                   cmSystemTools::UpperCase(config));
 }
+
+std::string cmGlobalNinjaMultiGenerator::OrderDependsTargetForTargetPrivate(
+  cmGeneratorTarget const* target, const std::string& config) const
+{
+  return cmStrCat(this->OrderDependsTargetForTarget(target, config),
+                  "_private");
+}
diff --git a/Source/cmGlobalNinjaGenerator.h b/Source/cmGlobalNinjaGenerator.h
index c43e27c..56a922c 100644
--- a/Source/cmGlobalNinjaGenerator.h
+++ b/Source/cmGlobalNinjaGenerator.h
@@ -349,6 +349,9 @@ public:
   virtual std::string OrderDependsTargetForTarget(
     cmGeneratorTarget const* target, const std::string& config) const;
 
+  virtual std::string OrderDependsTargetForTargetPrivate(
+    cmGeneratorTarget const* target, const std::string& config) const;
+
   void AppendTargetOutputs(cmGeneratorTarget const* target,
                            cmNinjaDeps& outputs, const std::string& config,
                            cmNinjaTargetDepends depends) const;
@@ -738,6 +741,9 @@ public:
   std::string OrderDependsTargetForTarget(
     cmGeneratorTarget const* target, const std::string& config) const override;
 
+  std::string OrderDependsTargetForTargetPrivate(
+    cmGeneratorTarget const* target, const std::string& config) const override;
+
 protected:
   bool OpenBuildFileStreams() override;
   void CloseBuildFileStreams() override;
diff --git a/Source/cmNinjaTargetGenerator.cxx b/Source/cmNinjaTargetGenerator.cxx
index 6187543..193cc0f 100644
--- a/Source/cmNinjaTargetGenerator.cxx
+++ b/Source/cmNinjaTargetGenerator.cxx
@@ -38,6 +38,7 @@
 #include "cmNinjaNormalTargetGenerator.h"
 #include "cmNinjaUtilityTargetGenerator.h"
 #include "cmOutputConverter.h"
+#include "cmPolicies.h"
 #include "cmRange.h"
 #include "cmRulePlaceholderExpander.h"
 #include "cmSourceFile.h"
@@ -169,6 +170,13 @@ std::string cmNinjaTargetGenerator::OrderDependsTargetForTarget(
     this->GeneratorTarget, config);
 }
 
+std::string cmNinjaTargetGenerator::OrderDependsTargetForTargetPrivate(
+  const std::string& config)
+{
+  return this->GetGlobalGenerator()->OrderDependsTargetForTargetPrivate(
+    this->GeneratorTarget, config);
+}
+
 // TODO: Most of the code is picked up from
 // void cmMakefileExecutableTargetGenerator::WriteExecutableRule(bool relink),
 // void cmMakefileTargetGenerator::WriteTargetLanguageFlags()
@@ -1020,6 +1028,45 @@ void cmNinjaTargetGenerator::WriteObjectBuildStatements(
       cmStrCat("Order-only phony target for ", this->GetTargetName());
     build.Outputs.push_back(this->OrderDependsTargetForTarget(config));
 
+    // Gather order-only dependencies on custom command outputs.
+    std::vector<std::string> ccouts;
+    std::vector<std::string> ccouts_private;
+    bool usePrivateGeneratedSources = false;
+    if (this->GeneratorTarget->Target->HasFileSets()) {
+      switch (this->GetGeneratorTarget()->GetPolicyStatusCMP0154()) {
+        case cmPolicies::WARN:
+        case cmPolicies::OLD:
+          break;
+        case cmPolicies::REQUIRED_ALWAYS:
+        case cmPolicies::REQUIRED_IF_USED:
+        case cmPolicies::NEW:
+          usePrivateGeneratedSources = true;
+          break;
+      }
+    }
+    for (cmCustomCommand const* cc : customCommands) {
+      cmCustomCommandGenerator ccg(*cc, config, this->GetLocalGenerator());
+      const std::vector<std::string>& ccoutputs = ccg.GetOutputs();
+      const std::vector<std::string>& ccbyproducts = ccg.GetByproducts();
+      ccouts.insert(ccouts.end(), ccoutputs.begin(), ccoutputs.end());
+      ccouts.insert(ccouts.end(), ccbyproducts.begin(), ccbyproducts.end());
+      if (usePrivateGeneratedSources) {
+        auto it = ccouts.begin();
+        while (it != ccouts.end()) {
+          cmFileSet const* fileset =
+            this->GeneratorTarget->GetFileSetForSource(
+              config, this->Makefile->GetOrCreateGeneratedSource(*it));
+          if (fileset &&
+              fileset->GetVisibility() != cmFileSetVisibility::Private) {
+            ++it;
+          } else {
+            ccouts_private.push_back(*it);
+            it = ccouts.erase(it);
+          }
+        }
+      }
+    }
+
     cmNinjaDeps& orderOnlyDeps = build.OrderOnlyDeps;
     this->GetLocalGenerator()->AppendTargetDepends(
       this->GeneratorTarget, orderOnlyDeps, config, fileConfig,
@@ -1029,17 +1076,8 @@ void cmNinjaTargetGenerator::WriteObjectBuildStatements(
     cm::append(orderOnlyDeps, this->Configs[config].ExtraFiles);
 
     // Add order-only dependencies on custom command outputs.
-    for (cmCustomCommand const* cc : customCommands) {
-      cmCustomCommandGenerator ccg(*cc, config, this->GetLocalGenerator());
-      const std::vector<std::string>& ccoutputs = ccg.GetOutputs();
-      const std::vector<std::string>& ccbyproducts = ccg.GetByproducts();
-      std::transform(ccoutputs.begin(), ccoutputs.end(),
-                     std::back_inserter(orderOnlyDeps),
-                     this->MapToNinjaPath());
-      std::transform(ccbyproducts.begin(), ccbyproducts.end(),
-                     std::back_inserter(orderOnlyDeps),
-                     this->MapToNinjaPath());
-    }
+    std::transform(ccouts.begin(), ccouts.end(),
+                   std::back_inserter(orderOnlyDeps), this->MapToNinjaPath());
 
     std::sort(orderOnlyDeps.begin(), orderOnlyDeps.end());
     orderOnlyDeps.erase(
@@ -1060,8 +1098,32 @@ void cmNinjaTargetGenerator::WriteObjectBuildStatements(
 
     this->GetGlobalGenerator()->WriteBuild(this->GetImplFileStream(fileConfig),
                                            build);
-  }
 
+    // Add order-only dependencies on custom command outputs that are
+    // private to this target.
+    this->HasPrivateGeneratedSources = !ccouts_private.empty();
+    if (this->HasPrivateGeneratedSources) {
+      cmNinjaBuild buildPrivate("phony");
+      cmNinjaDeps& orderOnlyDepsPrivate = buildPrivate.OrderOnlyDeps;
+      orderOnlyDepsPrivate.push_back(
+        this->OrderDependsTargetForTarget(config));
+
+      buildPrivate.Outputs.push_back(
+        this->OrderDependsTargetForTargetPrivate(config));
+
+      std::transform(ccouts_private.begin(), ccouts_private.end(),
+                     std::back_inserter(orderOnlyDepsPrivate),
+                     this->MapToNinjaPath());
+
+      std::sort(orderOnlyDepsPrivate.begin(), orderOnlyDepsPrivate.end());
+      orderOnlyDepsPrivate.erase(
+        std::unique(orderOnlyDepsPrivate.begin(), orderOnlyDepsPrivate.end()),
+        orderOnlyDepsPrivate.end());
+
+      this->GetGlobalGenerator()->WriteBuild(
+        this->GetImplFileStream(fileConfig), buildPrivate);
+    }
+  }
   {
     std::vector<cmSourceFile const*> objectSources;
     this->GeneratorTarget->GetObjectSources(objectSources, config);
@@ -1388,7 +1450,13 @@ void cmNinjaTargetGenerator::WriteObjectBuildStatement(
                    this->MapToNinjaPath());
   }
 
-  objBuild.OrderOnlyDeps.push_back(this->OrderDependsTargetForTarget(config));
+  if (this->HasPrivateGeneratedSources) {
+    objBuild.OrderOnlyDeps.push_back(
+      this->OrderDependsTargetForTargetPrivate(config));
+  } else {
+    objBuild.OrderOnlyDeps.push_back(
+      this->OrderDependsTargetForTarget(config));
+  }
 
   // If the source file is GENERATED and does not have a custom command
   // (either attached to this source file or another one), assume that one of
diff --git a/Source/cmNinjaTargetGenerator.h b/Source/cmNinjaTargetGenerator.h
index d41d86e..3f56113 100644
--- a/Source/cmNinjaTargetGenerator.h
+++ b/Source/cmNinjaTargetGenerator.h
@@ -81,6 +81,7 @@ protected:
   bool CompileWithDefines(std::string const& lang) const;
 
   std::string OrderDependsTargetForTarget(const std::string& config);
+  std::string OrderDependsTargetForTargetPrivate(const std::string& config);
 
   std::string ComputeOrderDependsForTarget();
 
@@ -228,6 +229,7 @@ protected:
 
 private:
   cmLocalNinjaGenerator* LocalGenerator;
+  bool HasPrivateGeneratedSources = false;
 
   struct ScanningFiles
   {
diff --git a/Source/cmPolicies.h b/Source/cmPolicies.h
index 26c141d..e894073 100644
--- a/Source/cmPolicies.h
+++ b/Source/cmPolicies.h
@@ -465,7 +465,11 @@ class cmMakefile;
     "file(REAL_PATH) resolves symlinks before collapsing ../ components.", 3, \
     28, 0, cmPolicies::WARN)                                                  \
   SELECT(POLICY, CMP0153, "The exec_program command should not be called.",   \
-         3, 28, 0, cmPolicies::WARN)
+         3, 28, 0, cmPolicies::WARN)                                          \
+  SELECT(                                                                     \
+    POLICY, CMP0154,                                                          \
+    "Generated files are private by default in targets using file sets.", 3,  \
+    28, 0, cmPolicies::WARN)
 
 #define CM_SELECT_ID(F, A1, A2, A3, A4, A5, A6) F(A1)
 #define CM_FOR_EACH_POLICY_ID(POLICY)                                         \
@@ -503,7 +507,8 @@ class cmMakefile;
   F(CMP0113)                                                                  \
   F(CMP0119)                                                                  \
   F(CMP0131)                                                                  \
-  F(CMP0142)
+  F(CMP0142)                                                                  \
+  F(CMP0154)
 
 #define CM_FOR_EACH_CUSTOM_COMMAND_POLICY(F)                                  \
   F(CMP0116)                                                                  \
diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index ace93e8..abbf29e 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -3201,6 +3201,11 @@ std::vector<std::string> cmTarget::GetAllInterfaceFileSets() const
   return result;
 }
 
+bool cmTarget::HasFileSets() const
+{
+  return !this->impl->FileSets.empty();
+}
+
 bool cmTargetInternals::CheckImportedLibName(std::string const& prop,
                                              std::string const& value) const
 {
diff --git a/Source/cmTarget.h b/Source/cmTarget.h
index b77ea0c..584856a 100644
--- a/Source/cmTarget.h
+++ b/Source/cmTarget.h
@@ -321,6 +321,8 @@ public:
   static std::string GetFileSetsPropertyName(const std::string& type);
   static std::string GetInterfaceFileSetsPropertyName(const std::string& type);
 
+  bool HasFileSets() const;
+
 private:
   template <typename ValueType>
   void StoreProperty(const std::string& prop, ValueType value);
diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index 9b9a53e..62c9628 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -242,6 +242,9 @@ if(CMAKE_GENERATOR MATCHES "Ninja")
   add_RunCMake_test(NinjaMultiConfig)
   set_property(TEST RunCMake.NinjaMultiConfig APPEND
     PROPERTY LABELS "CUDA")
+  add_RunCMake_test(NinjaPrivateDeps
+    -DCMAKE_C_OUTPUT_EXTENSION=${CMAKE_C_OUTPUT_EXTENSION}
+    -DRunCMake_GENERATOR_IS_MULTI_CONFIG=${_isMultiConfig})
 endif()
 add_RunCMake_test(CTest)
 
diff --git a/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-EmptyFileSet-Source-check.cmake b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-EmptyFileSet-Source-check.cmake
new file mode 100644
index 0000000..7658930
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-EmptyFileSet-Source-check.cmake
@@ -0,0 +1,3 @@
+if (EXISTS ${RunCMake_TEST_BINARY_DIR}/empty.cpp)
+  set(RunCMake_TEST_FAILED "Compiled source generated before compilation of consumers.")
+endif()
diff --git a/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-EmptyFileSet-check.cmake b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-EmptyFileSet-check.cmake
new file mode 100644
index 0000000..3287a65
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-EmptyFileSet-check.cmake
@@ -0,0 +1,3 @@
+if (NOT EXISTS ${RunCMake_TEST_BINARY_DIR}/empty.cpp)
+  set(RunCMake_TEST_FAILED "Compiled source did not generate.")
+endif()
diff --git a/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-NoFileSet-Source-check.cmake b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-NoFileSet-Source-check.cmake
new file mode 100644
index 0000000..9e99ed8
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-NoFileSet-Source-check.cmake
@@ -0,0 +1,3 @@
+if (NOT EXISTS ${RunCMake_TEST_BINARY_DIR}/none.cpp)
+  set(RunCMake_TEST_FAILED "Private source dependency used for target without filesets.")
+endif()
diff --git a/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-PrivateFileSet-Source-check.cmake b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-PrivateFileSet-Source-check.cmake
new file mode 100644
index 0000000..dd814c9
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-PrivateFileSet-Source-check.cmake
@@ -0,0 +1,3 @@
+if (EXISTS ${RunCMake_TEST_BINARY_DIR}/private.h)
+  set(RunCMake_TEST_FAILED "Private header generated before compilation.")
+endif()
diff --git a/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-PrivateFileSet-check.cmake b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-PrivateFileSet-check.cmake
new file mode 100644
index 0000000..357b8c0
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-PrivateFileSet-check.cmake
@@ -0,0 +1,3 @@
+if (NOT EXISTS ${RunCMake_TEST_BINARY_DIR}/private.h)
+  set(RunCMake_TEST_FAILED "Private header generated before compilation.")
+endif()
diff --git a/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-PublicFileSet-Source-check.cmake b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-PublicFileSet-Source-check.cmake
new file mode 100644
index 0000000..cfceb7a
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW-Build-PublicFileSet-Source-check.cmake
@@ -0,0 +1,3 @@
+if (NOT EXISTS ${RunCMake_TEST_BINARY_DIR}/public.h)
+  set(RunCMake_TEST_FAILED "Public header did not generate before compilation.")
+endif()
diff --git a/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW.cmake b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW.cmake
new file mode 100644
index 0000000..3330269
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-NEW.cmake
@@ -0,0 +1,2 @@
+cmake_policy(SET CMP0154 NEW)
+include(CMP0154-common.cmake)
diff --git a/Tests/RunCMake/NinjaPrivateDeps/CMP0154-OLD-Build-EmptyFileSet-Source-check.cmake b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-OLD-Build-EmptyFileSet-Source-check.cmake
new file mode 100644
index 0000000..8ee1ad4
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-OLD-Build-EmptyFileSet-Source-check.cmake
@@ -0,0 +1,3 @@
+if (NOT EXISTS ${RunCMake_TEST_BINARY_DIR}/empty.cpp)
+  set(RunCMake_TEST_FAILED "Policy CMP0154 set to OLD but using new behavior compiled sources.")
+endif()
diff --git a/Tests/RunCMake/NinjaPrivateDeps/CMP0154-OLD-Build-PrivateFileSet-Source-check.cmake b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-OLD-Build-PrivateFileSet-Source-check.cmake
new file mode 100644
index 0000000..25c23d7
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-OLD-Build-PrivateFileSet-Source-check.cmake
@@ -0,0 +1,3 @@
+if (NOT EXISTS ${RunCMake_TEST_BINARY_DIR}/private.h)
+  set(RunCMake_TEST_FAILED "Policy CMP0154 set to OLD but using new behavior private headers.")
+endif()
diff --git a/Tests/RunCMake/NinjaPrivateDeps/CMP0154-OLD.cmake b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-OLD.cmake
new file mode 100644
index 0000000..691530c
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-OLD.cmake
@@ -0,0 +1,2 @@
+cmake_policy(SET CMP0154 OLD)
+include(CMP0154-common.cmake)
diff --git a/Tests/RunCMake/NinjaPrivateDeps/CMP0154-common.cmake b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-common.cmake
new file mode 100644
index 0000000..a9e6d20
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/CMP0154-common.cmake
@@ -0,0 +1,45 @@
+enable_language(CXX)
+
+function(copy_file file dest)
+  add_custom_command(
+    OUTPUT ${CMAKE_BINARY_DIR}/${dest}
+    COMMAND ${CMAKE_COMMAND} -E copy
+      ${CMAKE_SOURCE_DIR}/${file} ${CMAKE_BINARY_DIR}/${dest}
+  )
+endfunction()
+
+copy_file(header.h.in private.h)
+copy_file(header.h.in public.h)
+copy_file(source.cpp.in empty.cpp)
+copy_file(source.cpp.in none.cpp)
+
+add_library(HelloLib_PrivateFileSet STATIC hello_lib.cpp)
+target_sources(HelloLib_PrivateFileSet
+  PRIVATE FILE_SET HEADERS
+    BASE_DIRS ${CMAKE_BINARY_DIR}
+    FILES ${CMAKE_BINARY_DIR}/private.h
+)
+
+add_library(HelloLib_PublicFileSet STATIC hello_lib.cpp)
+target_sources(HelloLib_PublicFileSet
+  PUBLIC FILE_SET HEADERS
+    BASE_DIRS ${CMAKE_BINARY_DIR}
+    FILES ${CMAKE_BINARY_DIR}/public.h
+)
+
+add_library(HelloLib_EmptyFileSet STATIC hello_lib.cpp empty.cpp)
+target_sources(HelloLib_EmptyFileSet
+  PUBLIC FILE_SET HEADERS
+)
+
+add_library(HelloLib_NoFileSet STATIC hello_lib.cpp none.cpp)
+
+function(hello_executable name)
+  add_executable(Hello_${name} hello.cpp)
+  target_link_libraries(Hello_${name} PRIVATE HelloLib_${name})
+endfunction()
+
+hello_executable(PrivateFileSet)
+hello_executable(PublicFileSet)
+hello_executable(EmptyFileSet)
+hello_executable(NoFileSet)
diff --git a/Tests/RunCMake/NinjaPrivateDeps/CMakeLists.txt b/Tests/RunCMake/NinjaPrivateDeps/CMakeLists.txt
new file mode 100644
index 0000000..54a4d62
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/CMakeLists.txt
@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.26)
+project(${RunCMake_TEST} NONE)
+include(${RunCMake_TEST}.cmake)
diff --git a/Tests/RunCMake/NinjaPrivateDeps/RunCMakeTest.cmake b/Tests/RunCMake/NinjaPrivateDeps/RunCMakeTest.cmake
new file mode 100644
index 0000000..e821185
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/RunCMakeTest.cmake
@@ -0,0 +1,30 @@
+include(RunCMake)
+
+function(compile_source test target)
+  if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
+    set(config "Debug/")
+  endif()
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/${test}-build)
+  set(RunCMake_TEST_NO_CLEAN 1)
+  run_cmake_command(${test}-Build-${target}-Source ${CMAKE_COMMAND} --build .
+    --target CMakeFiles/Hello_${target}.dir/${config}hello.cpp${CMAKE_C_OUTPUT_EXTENSION})
+endfunction()
+
+function(compile_target test target)
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/${test}-build)
+  set(RunCMake_TEST_NO_CLEAN 1)
+  run_cmake_command(${test}-Build-${target} ${CMAKE_COMMAND} --build .
+    --target Hello_${target})
+endfunction()
+
+run_cmake(CMP0154-OLD)
+compile_source(CMP0154-OLD PrivateFileSet)
+compile_source(CMP0154-OLD EmptyFileSet)
+
+run_cmake(CMP0154-NEW)
+compile_source(CMP0154-NEW PrivateFileSet)
+compile_target(CMP0154-NEW PrivateFileSet)
+compile_source(CMP0154-NEW PublicFileSet)
+compile_source(CMP0154-NEW NoFileSet)
+compile_source(CMP0154-NEW EmptyFileSet)
+compile_target(CMP0154-NEW EmptyFileSet)
diff --git a/Tests/RunCMake/NinjaPrivateDeps/header.h.in b/Tests/RunCMake/NinjaPrivateDeps/header.h.in
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/header.h.in
diff --git a/Tests/RunCMake/NinjaPrivateDeps/hello.cpp b/Tests/RunCMake/NinjaPrivateDeps/hello.cpp
new file mode 100644
index 0000000..34fabe9
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/hello.cpp
@@ -0,0 +1,6 @@
+#include "hello_lib.h"
+
+int main()
+{
+  say_hello();
+}
diff --git a/Tests/RunCMake/NinjaPrivateDeps/hello_lib.cpp b/Tests/RunCMake/NinjaPrivateDeps/hello_lib.cpp
new file mode 100644
index 0000000..d67113f
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/hello_lib.cpp
@@ -0,0 +1,8 @@
+#include "hello_lib.h"
+
+#include <iostream>
+
+void say_hello()
+{
+  std::cout << "hello" << std::endl;
+}
diff --git a/Tests/RunCMake/NinjaPrivateDeps/hello_lib.h b/Tests/RunCMake/NinjaPrivateDeps/hello_lib.h
new file mode 100644
index 0000000..3b4775f
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/hello_lib.h
@@ -0,0 +1 @@
+void say_hello();
diff --git a/Tests/RunCMake/NinjaPrivateDeps/source.cpp.in b/Tests/RunCMake/NinjaPrivateDeps/source.cpp.in
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/Tests/RunCMake/NinjaPrivateDeps/source.cpp.in
diff --git a/Tests/RunCMake/TargetPolicies/PolicyList-stderr.txt b/Tests/RunCMake/TargetPolicies/PolicyList-stderr.txt
index 0d8e4c9..7e91b76 100644
--- a/Tests/RunCMake/TargetPolicies/PolicyList-stderr.txt
+++ b/Tests/RunCMake/TargetPolicies/PolicyList-stderr.txt
@@ -37,6 +37,7 @@
    \* CMP0119
    \* CMP0131
    \* CMP0142
+   \* CMP0154
 
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)